Add repr flag and length to docs

Author: jschendel

doc/source/api.rst

@@ -1623,6 +1623,7 @@ IntervalIndex Components
    IntervalIndex.right
    IntervalIndex.mid
    IntervalIndex.closed
+   IntervalIndex.length
    IntervalIndex.values
    IntervalIndex.is_non_overlapping_monotonic
 
@@ -1995,6 +1996,7 @@ Properties
     Interval.closed_left
     Interval.closed_right
     Interval.left
+    Interval.length
     Interval.mid
     Interval.open_left
     Interval.open_right

pandas/_libs/interval.pyx

@@ -63,7 +63,7 @@ cdef class IntervalMixin(object):
             return self.right - self.left
         except TypeError:
             # length not defined for some types, e.g. string
-            msg = 'cannot compute length between {left} and {right}'
+            msg = 'cannot compute length between {left!r} and {right!r}'
             raise TypeError(msg.format(left=self.left, right=self.right))
 
 

pandas/core/indexes/interval.py

@@ -116,18 +116,26 @@ class IntervalIndex(IntervalMixin, Index):
        The indexing behaviors are provisional and may change in
        a future version of pandas.
 
-    Attributes
+    Parameters
     ----------
-    left, right : array-like (1-dimensional)
-        Left and right bounds for each interval.
+    data : array-like (1-dimensional)
+        Array-like containing Interval objects from which to build the
+        IntervalIndex
     closed : {'left', 'right', 'both', 'neither'}, default 'right'
         Whether the intervals are closed on the left-side, right-side, both or
         neither.
     name : object, optional
         Name to be stored in the index.
     copy : boolean, default False
         Copy the meta-data
+
+    Attributes
+    ----------
+    left
+    right
+    closed
     mid
+    length
     values
     is_non_overlapping_monotonic